Medical therapy with π- mesons

Physical and biological aspects led to the realization of cancer therapy with π- mesons. The pions are produced by collision of the protons with target material. They are focused into the treatment volume. Two methods are developed to scan this volume in a 3-dimensional way. The dosimetric system has to take into account that the dose contains spatially mixed LET contributions. CT-slices of the patient serve as a basis for therapy planning. As experience grew, deeper lying tumors were treated. The expectations of the project have recently been accomplished. Even so, it is too early to make conclusive statements about clinical data; however, the results permit us to look optimistically into the future. (orig.)